PROCESS · JUNE 2026

# Charring hardwood: notes on our Yakisugi process

A Japanese way of protecting cedar with fire, adapted for hardwood and for a table you eat at every day.

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5 MIN READ

Every piece in EMBER is finished by fire. Before we explain how, it is worth knowing where the method comes from, and why it was never meant to be decoration.

## Burnt cedar

Yakisugi joins two Japanese words: *yaki*, to burn or char, and *sugi*, the Japanese cedar *Cryptomeria japonica*. In North America it is usually called shou sugi ban, a reading of the same characters that is widely regarded as a mistranslation. We use the original.

The technique developed in western Japan and became widespread during the Edo period, between the early seventeenth and late nineteenth centuries. It was a builder’s method, not a furniture maker’s. Charred boards clad houses, storehouses, and fences, most of all in crowded towns where wooden buildings stood close together and fire was a constant threat.

The traditional burn is simple and fast. Three long boards are bound into a triangular flue and stood on end over a small fire. The chimney draws the flame up the inside faces, and within minutes they are charred. The boards are pulled apart, doused with water, and left to cool.

## What fire does to wood

Heat turns the outer layer of a board into carbon, and that layer does the work. It is harder to ignite than raw wood, it offers nothing for fungi or insects to feed on, and it does not grey and split in sunlight the way bare timber does. Beneath it sits a thin band of heat-treated wood; beneath that, the board is unchanged.

The texture comes from the grain. Wood grows in alternating bands, soft earlywood in spring and denser latewood in summer. Fire and brushing take the soft bands first and leave the hard ones standing, so the figure of the board ends up in relief.

The char is not something we apply; it is the surface of the board itself.

## Why hardwood is different

Sugi is soft and fast-growing, with a wide gap between its earlywood and latewood, and it chars quickly into the deep, crackled pattern known as alligator skin. The hardwoods we char are denser and more even. They take longer to burn, the crackle is finer, and when the loose char is brushed away the grain rises in a low, even relief rather than deep ridges.

That changes the job. A dense board needs more heat, more time, and more attention to stay even across a wide surface, and there is no hiding a cold patch on a six-foot round top. It is why Knob, the table EMBER is built around, is the longest finishing job in our shop.

EMBER · KNOB, LEFT · SLAB, RIGHT · CHARRED, BRUSHED AND OILED

## How we do it

01 · CHAR
Every surface is burned by hand to a full alligator skin, a section at a time, until the whole piece reads as one even black.

02 · BRUSH
Most of that char is brushed away: wire first, then softer bristle, until the loose carbon is gone and the grain stands up under the fingertips.

03 · OIL
What remains is oiled. The oil deepens the black and binds the surface, leaving a finish that sheds water and takes decades of hands without wearing thin.

## Indoors, the brief changes

On a building, char is armour. On a dining table, protection matters less than the surface itself: a black you can read with your fingertips, and grain you can still see at its darkest. So we brush further than an exterior board would ever be brushed, until nothing comes away on a hand or a napkin.

The finish is meant to be kept, not replaced. Wipe it with a damp cloth. When the surface begins to look dry, a fresh coat of oil brings it back. The char itself goes nowhere; it is part of the board.

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SOURCES & FURTHER READING

[Using Charred Wood for Exteriors and Interiors BNP MEDIA CE CENTER](https://continuingeducation.bnpmedia.com/architect/courses/nakamoto-forestry-north-america/using-charred-wood-for-exteriors-and-interiors/)
[Torch It! All About Yakisugi Charred Timber Finish MAKE:](https://makezine.com/projects/torch-it-all-about-yakisugi-charred-timber-finish/)
[Yakisugi: Authentic Japanese Charred Wood Technique BURNEDWOOD](https://burnedwood.com/en/glossary/yakisugi/)
[An Exploration of Yakisugi GOODLAND](https://hellogoodland.com/blogs/news/exploration-of-yakisugi)

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Published 2026-06 · Process · https://rohnstudio.com/blog/yakisugi/